Understanding NCLEX EKG Rhythms

Are you preparing for your NCLEX exam?

Do you struggle with understanding 12 Lead EKG rhythms? I know when I was first learning them in nursing school I thought I was WAY in over my head with trying to comprehend them. However one thing I have learned is that they are not really that challenging once you know how to study for them. Take for example, the image below.

nclex tips

Now the first thing you have to understand is what each “beat” means on the rhythm. You have the P wave, the QRS complex and the T wave. Now there’s something called an SA node on the atrium of the heart which is the top half of the heart. What this SA node does, is that it sends an impulse which causes the atrium to contract. When the atrium contracts normally it represents the “P wave” which is also called atrial depolarization.



After this happens, there’s another node that’s located on top of the ventricles of the heart which is the bottom half of the heart. This node is called the “AV node”. This impulse will fire down to a canal in the heart called the Bundle of His which will then disperse into the Purkinje fibers located inside of the ventricles and this will cause the ventricles to contract. The ventricles contracting is a reflection of the QRS complex also known as ventricular depolarization.



Then next the ventricles will relax which is the reflection of the T wave or also known as ventricular repolarization. In the very first image as long as the beats continue to all be present and they are consistent this would reflect a normal sinus rhythm. Like the one posted below.

nclex tips



Now there is a normal and there is abnormal. The normal time that it takes for the atrium to contract until the ventricles contract is 0.12 to 0.20 seconds which is the PR interval. And the normal time for the ventricles to contract which is the QRS complex is less than 0.12 seconds. Here is one question you need to ask yourself when it comes down to understanding 12 lead EKG rhythms and that is

“What are the nursing conditions/diseases would I see this rhythm in”?


So in the above image that is a reflection of a normal sinus rhythm but however who would you see sinus bradycardia in? Or sinus tachycardia?

This is how you think more critically in order to help you prepare more adequately for 12 Lead ECGS.

Learn more by watching the 10 minute video below.



Would you like to work with Nurse Chioma through one on one coaching? Simply send us an email at nursechioma@choosingnursing.net and we will respond to you promptly where you will have access to the entire program plus private tutoring sessions with Nurse Chioma.


Thanks for sharing!

*Image is taken from wikimedia.org

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